Yıldız Technical University Research Information System
Not a member yet
91324 research outputs found
Sort by
ANALYSIS OF CRITERIA WEIGHTING METHODS AND A NEW METHOD PROPOSAL
No full textWhen making decisions about problems we experience in real life, there is usually more than one factorthat affects this decision. These factors can be interdependent or independent. Multi-criteria decision-making (MCDM) is an engineering tool that makes decision-making more accurate in these cases bybasing it on mathematical or logical foundations. Determining criteria weights is a significant challengein multi-criteria analysis models. Selecting the right method for establishing these weights is a vital stepin MCDM that can complicate the overall decision-making process. Many studies have been done oncriterion weighting, and criterion weighting methods with different purposes and applications have beendeveloped. AHP (Analytic Hierarchy Process), TOPSIS (Technique for Order of Preference by Similarityto Ideal Solution), SWARA (Stepwise Weight Assessment Ratio Analysis), FUCOM (Full ConsistencyMethod), and BWM (Best-Worst Method) are some of the most popular methods in literature. This studyexamines methods’ implementation, ease, consistency, advantages, and disadvantages. After comparingthese methods with each other, a new method is proposed. The advantages of the new method, which isunder development, and the issues that need to be improved are explained. This method is based on themakers scoring the criteria to make the evaluation process easier for decision-makers. Criteria weightsare then calculated based on the domination relationship between the criteria.</p
Investigation of the effects of direct integration methods and their parameters on pounding in different impact models
No full textNew Insights into Meteorological and Hydrological Drought Modeling: A Comparative Analysis of Parametric and Non-Parametric Distributions
No full textAccurate drought monitoring depends on selecting an appropriate cumulative distribution function (CDF) to model the original data, resulting in the standardized drought indices. In the numerous research studies, while rigorous validation was not made by scrutinizing the model assumptions and uncertainties in identifying theoretical drought CDF models, such oversights lead to biased representations of drought evaluation and characteristics. This research compares the parametric theoretical and empirical CDFs for a comprehensive evaluation of standardized Drought Indices. Additionally, it examines the advantages, disadvantages, and limitations of both empirical and theoretical distribution functions in drought assessment. Three drought indices, Standardized Precipitation Index (SPI), Streamflow Drought Index (SDI), and Standardized Precipitation Evapotranspiration Index (SPEI), cover meteorological and hydrological droughts. The assessment spans diverse applications, covering different climates and regions: Durham, United Kingdom (SPEI, 1868–2021); Konya, Türkiye (SPI, 1964–2022); and Lüleburgaz, Türkiye (SDI, 1957–2015). The findings reveal that theoretical and empirical CDFs demonstrated notable discrepancies, particularly in long-term hydrological drought assessments, where underestimations reached up to 50%, posing risks of misinformed conclusions that may impact critical drought-related decisions and policymaking. Root Mean Squared Error (RMSE) for SPI3 between empirical and best-fitted CDF was 0.087, and between empirical and Gamma it was 0.152. For SDI, it ranged between 0.09 and 0.143. The Mean Absolute Error (MAE) for SPEI was approximately 0.05 for all timescales. Additionally, it concludes that empirical CDFs provide more reliable and conservative drought assessments and are free from the constraints of model assumptions. Both approaches gave approximately the same drought duration with different intensities regarding drought characteristics. Due to the complex process of drought events and different definitions of drought events, each drought event must be studied separately, considering its effects on different sectors.</jats:p
Nonlinearity in the trend of GRACE time series: improving understanding of global total water storage changes over two decades
No full textThe mediating role of cognitive emotion regulation skills in the relationship between romantic relationship satisfaction and eating attitudes
No full textBackground Romantic relationship satisfaction has been linked to psychological outcomes, including emotional well-being and eating behaviors. However, the mechanisms underlying this relationship remain unclear. This study examines the mediating role of cognitive emotion regulation strategies-particularly catastrophizing-in the relationship between romantic relationship satisfaction and eating attitudes. Methods A cross-sectional study was conducted with 355 university students. Participants completed the Relationship Satisfaction Scale, the Cognitive Emotion Regulation Questionnaire (CERQ), and the Eating Attitudes Test-26 (EAT-26). Structural equation modeling (SEM) was performed using AMOS and R with robust maximum likelihood estimation. Model fit was evaluated using chi 2/df, CFI, GFI, RMSEA, and SRMR. Results Catastrophizing significantly mediated the relationship between romantic relationship satisfaction and eating attitudes. Romantic relationship satisfaction was negatively associated with catastrophizing (beta = -0.18, p = .028), and catastrophizing was positively associated with problematic eating attitudes (beta = 0.35, p < .001). The direct effect of romantic relationship satisfaction on eating attitudes was not statistically significant (beta = -0.12, p = .104), indicating full mediation. Acceptance did not significantly mediate the relationship (p = .348). Gender differences were observed: women scored significantly higher on rumination, dieting, and bulimia/food preoccupation (p < .05). Conclusions These findings highlight the role of maladaptive cognitive emotion regulation-specifically catastrophizing-in linking romantic relationship dissatisfaction with disordered eating attitudes. Targeting catastrophizing in interventions may improve both relationship satisfaction and eating behaviors
REAL TIME CHANNEL DETECTION IN SONOBUOY SYSTEMS USING THE ENERGY DETECTION METHOD
No full textBu çalışmada, sonoboyThis study</p
Urbanization Patterns and Their Influence on Educational Outcomes: Insights from the Provincial Wellbeing Index Data of Türkiye
No full textHİDRO DEPOLAMA DESTEKLİ AGROFOTOVOLTAİK SİSTEMLERİN TASARIMI VE ANALİZİ
No full textGünümüzde artan nüfus ile gelecekte enerji talebinin karşılanıp karşılanmayacağı bilinmemekle beraber fosil yakıtların enerji ihtiyacını karşılamak amacıyla kullanılması çeşitli tüketim problemlerini ortaya çıkarmaktadır. Fosil yakıtların zamanla kullanımının artması karbon emisyonu artışına sebep olarak sera etkisine ve küresel ısınmaya etki etmektedir. Aynı zamanda ekosisteme zarar vererek hava kirliliğine sebebiyet vermektedir. Fosil yakıtların bu olumsuz etkilerinin sebebi ile yenilenebilir enerji kaynaklarına yönelinerek enerji verimliliği amaçlanmıştır. İklim değişiklikleri, tarımsal su sıkıntıları ve artan enerji talebi enerji sektörü ve tarım faaliyetlerini entegre çalışmaları gerekliliğini ortaya çıkarmıştır. Kırsal ve çorak alanlarda suya ve enerjiye erişimin kısıtlı olması gıda sektöründe de tehdit oluşturmaktadır. Bu amaçla agrofotovoltaik sistemler ile aynı tarım arazisi içerisinde güneş panelleri ile elektrik üretiminin yapılmasına ve aynı zamanda tarımsal faaliyetlere de olanak sağlanmıştır. Güneş panelleri yerden belirli yüksekliklere konumlandırılarak enerji üretimi yapılırken tarım yetiştiriciliğinin de devamlılığı hedeflenmiştir. Fotovoltaik sistemlerin süreksiz olması dengesizliklere neden olmaktadır ve bu sistemler hidroelektrik depolama ile entegre edilerek enerji üretimi süreksizliğini önlemek amaçlanmıştır ve tarım-enerji-su döngüsü ile kaynak verimliliği arttırılmıştır. Bu çalışmada, hidroelektrik depolama teknolojisi ve güneş enerjisi ile tarımsal üretimi amaçlayan agrofotovoltaik sistemlerin entegre çalışması ele alınmıştır. Tarım arazisinde güneş panelleri ile üretilen elektrik enerjisi pompaj depolamalı hidroelektrik sistem aracılığıyla depolanarak sürdürülebilirlik ve enerji sürekliliği değerlendirilmiştir.</p
Numerical and experimental investigation of the effect of motor rotation speed and direction on the velocity and temperature distribution inside the cavity in domestic oven with fan Fanlı pişirici cihazlarda motor dönüş devri ve yönünün kavite içi hız ve sıcaklık dağılımına etkisinin sayısal ve deneysel incelenmesi
No full textToday, as consumers become more environmentally conscious, the demand for energy-efficient household appliances is increasing. Therefore, with the development of innovative designs and production technologies, the production of environmentally friendly home appliances is on the agenda. Within the scope of this study, in-cavity circulation flow rate, velocity and temperature distribution at different rotation speeds and directions of the fan-motor group in domestic oven with fan were investigated numerically and experimentally. In this study, the motor rotation speed in the cavity was examined from 600 rpm to 2400 rpm. At the same time, velocity data were taken experimentally with a hot wire probe from local points on three planes determined in the cavity. In parallel with the study, different turbulence models were examined using Ansys Fluent program in the numerical solution phase. Among the turbulence models examined, the k-w SST model was found to be the most stable and accurate model. As a result of the study, experimental and numerical results were found to be compatible with each other. It was observed that as the rotational speed of the fan-motor group increased, the average velocity and standard deviation values on the planes in the cavity also increased. For homogeneous cooking, it was determined that the standard deviation value on the planes was the minimum and the average temperature on the planes was the closest to the targeted temperature with a motor rotation speed of ~2272 rpm and clockwise motor rotation direction. When the outputs of the numerical thermal studies were compared with the experimental data, the highest deviation of 3% was found